两种含有[Mo8O26]簇骼的化合物的光谱研究

合成了两种具有含有β-Mo8O26]4-簇阴离子的新型化合物: H(4,4'-bipy)]2K2Mo8O26](Ⅰ)和H3NaMo8O26](4,4'-bipy)5(H2O)4 (Ⅱ), 用FTIR, NIR-Raman, UV-Vis DRS和荧光光谱等研究手段进行光谱研究, 探讨其结构与性能的关系. 虽然这两个化合物中阴离子类似, 都含有β-Mo8O26]4-簇骼基元, 但它们与碱金属的连接方式不同, 其FTIR和NIR-Raman光谱的特征振动频率与其结构相关;化合物Ⅰ和Ⅱ的UV-Vis DRS光谱显示, 在250～300 nm有宽的紫外吸收谱带;化合物Ⅰ的稳态荧光光谱观察到分别以350 nm激发下在450～650 nm处产生一个宽的发射峰;化合物Ⅱ在325 nm激发下在400～550 nm处产生一个发射峰. 化合物Ⅰ在不同温度下稳态固体荧光光谱随着温度的下降, 荧光发射强度增强, 其时间分辨固体荧光光谱的荧光寿命随着温度的降低而增长.

Spectral Study of Two Compounds of Molybdate Salt with β-[Mo8O26] Anion

Two compounds of organic molybdate-alkali salt: H(4,4'-bipy)]2K2Mo8O26](I) and H3 Na Mo8 O26] (4,4'-bipy)5 (H2O)4 (II), with beta-Mo8O26]4- anion, were synthesized. The relationship between their properties and structures was studied by using FTIR, Raman, NIR-Vis and fluorescence etc. They possess isolating beta-Mo8O26]4- anion, whose terminal O atoms combine with alkali. The FTIR and Raman spectra showed that the vibrational frequencies of the group are related to the structure of the materials. In UV-Vis spectra of compound (I) and (II), there is a characteristic wide peak at 280-300 nm. The fluorescence spectra of compound (I) and (II) were studied, which showed that the wide emission peak is from 450 to 650 nm and excited by 350 nm for compound (I), and the emission peak is from 400 to 550 nm and excited by 325 nm for compound (II). For compound (I), the intensity of emission becomes stronger with decreasing of temperature, and so does the fluorescence lifetime.